LOS ANGELES (MCT) — Criminal charges will not be filed against a U.S. Border Patrol agent who shot and killed a 15-year-old Mexican boy on the Texas-Mexico border in 2010 because the shooting was a reasonable use of force and within agency guidelines, the Justice Department announced Friday.

The Mexican Foreign Ministry said in a statement that it “profoundly laments and expresses its most energetic rejection” of the Justice Department decision and noted that Mexico had sought the agent’s extradition.

The incident occurred June 7, 2010, in the area separating El Paso and Ciudad Juarez. The agent opened fire on a group of Mexicans who were throwing rocks at him as he attempted to arrest an illegal immigrant. Sergio Hernandez Guereca, who was in a spillway of the Rio Grande, was shot in the face and killed.

The Justice Department said a team of experienced prosecutors and agents concluded that there was insufficient evidence to charge the agent with homicide.

In a statement, the department said the agent’s actions constituted a reasonable use of force and self-defense “in response to the threat created by a group of smugglers hurling rocks at the agent and his detainee.”

The department added that there were no grounds to charge the agent with violating the boy’s civil rights.

“Accident, mistake, misperception, negligence and bad judgment are not sufficient to establish a federal criminal civil rights violation,” the statement said, adding that civil rights statutes did not apply because Hernandez Guereca was not on U.S. territory.

The Mexican Foreign Ministry, however, said it considers the case still open. In its statement the ministry also said the Mexican government would assist the boy’s family as it pursues a civil case in U.S. courts.